This project investigates the roles of autonomic nervous system (ANS) activity and attention and their interrelationships in the pathology, etiology, and prognosis of psychiatric disorders and studies their underlying biological and psychological processes. ANS activity is assessed by peripheral measures such as skin conductance and heart rate. Subjects are tested under conditions of rest, presentation of tones, and performance on reaction time tests of attention. Recent findings: 1) Adolescents with Childhood-onset Schizophrenia showed excessive resting ANS activity but lower than normal ANS activity during a task, low responsivity to novel and meaningful stimuli, and an irregular course of habituation. These results are similar to our previous findings in adult schizophrenia. 2) On two tests of attention using reaction time protocols that have shown characteristic patterns of deficits in adult schizophrenia, similar deficits were found in the childhood-onset group. Both the above findings support the hypothesis of continuity between childhood-onset and adult-onset schizophrenia. 3) A group of children, called Multidimensionally Impaired' who showed some clinical resemblance to schizophrenia but did not meet diagnostic criteria for that disorder, were quite distinct from the schizophrenia group in their pattern of ANS activity, but had similar attention deficits. 4) Adult schizophrenia patients had normal reaction times of saccadic eye movements with constant and variable foreperiods and no differential foreperiod affects. However they showed characteristic slow reaction time and exaggerated foreperiod effects on manual reaction time compared to controls. Future plans: Compare the adult schizophrenic group to normal controls, patients with affective disorders, and patients with closed head injuries and frontal lobe lesions tested ont he same protocol. Study differences in ANS activity and attention in relation to symptoms. Investigate biological mechanisms by correlating these variables with metabolites of biogenic amines from CSF and with brain structure and activity as revealed by CT, MRI, and PET scans.